Aristotle is generally considered a genius of towering stature and the depth and breadth of his work are testament to this; however, by most accounts, and despite being progressive in many ways, he can be portrayed as a bigot. By today’s standards his views on women and other races would, for the most part, be regarded unfavorably. This brings to mind other philosophers with outstanding philosophical accomplishments but yet held some remarkably unenlightened positions. Heidegger was, famously, a Nazi and never really renounced his support. Kant once weighed in on an opinion given by black man who treated his wives harshly and suggested that the harsh treatment was the proper way to keep women in line; Kant’s own reaction was that there might have been something to this advice except that it must be dismissed prima facie on the grounds that the person giving the advice was black.
Argumentum ad hominem would seem to immunize the works of all these notable philosophers in the sense that the logical merit of their work should stand on its own -- and this is correct. However, since the works themselves are gargantuan and complex and cannot be analyzed purely logically, would we be right to approach their views, particularly their ethics, with heightened suspicion and scrutiny on the basis of such evidence?
Some may claim that the social context of these philosophers must be taken into account, but if this was the case then shouldn’t their social context be taken into account for all their work and thus feed further into the question above and render the interpretation of their already difficult works even more intractable?